Hi,
I have a server running CentOS 5.5 with KVM capabilities. I need to migrate all the VMs to another server with the exact same hardware specs. The problem is it is running on individual harddisks, not shared storage. What is the best way to migrate to minimise downtime?
Thanks!
YongSan
One way would be to boot the VMs with a product like Acronis or Ghost, and create an image of the VM's drive(s).
Then create a new VM on the 2nd server that has nics with the same MAC addresses as the old VM, and storage with the same sizes, and restore the image there.
On 24/06/10 7:17 AM, "Poh Yong Hwang" yongsan@gmail.com wrote:
I have a server running CentOS 5.5 with KVM capabilities. I need to migrate all the VMs to another server with the exact same hardware specs. The problem is it is running on individual harddisks, not shared storage. What is the best way to migrate to minimise downtime?
I've had good success using dd and nc (netcat) to copy the contents of a disk or disk image from one machine to another, and verifying the copy was successful with a md5sum or sha1sum of both the original and copied disk.
Kelvin
I often use rsync -a for remote systems or cp -a for local systems. I've also used dd. You can have dd output to stdout, pipe it to ssh and have ssh output to dd on the other end.
You can also connect to a SAN device on the source and dd from the local block device to the SAN device.
Lots of ways to do it ;)
Cheers,
C.J.
On Thu, 2010-06-24 at 10:52 -0400, Kelvin Edmison wrote:
On 24/06/10 7:17 AM, "Poh Yong Hwang" yongsan@gmail.com wrote:
I have a server running CentOS 5.5 with KVM capabilities. I need to migrate all the VMs to another server with the exact same hardware specs. The problem is it is running on individual harddisks, not shared storage. What is the best way to migrate to minimise downtime?
I've had good success using dd and nc (netcat) to copy the contents of a disk or disk image from one machine to another, and verifying the copy was successful with a md5sum or sha1sum of both the original and copied disk.
Kelvin
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Create a new virtual machine on your storage. After this, boot some Linux distribution in your new virtual machine (I like SysrescueCD). Enable your ssh server, change the root password and so and back to your old virtual server and type:
# dd if=/dev/sda | ssh root@(new_vm) "(dd of=/dev/sda)"
Type the root password, shutdown the old VM and reboot your new vm.
(PS: You don't need to shutdown the old vm to this proccess).
I do this everytime, I don't like copy the HD files using cp, tar or rsync because it try to copy the /proc, /dev and a lot virtual devices. Using dd it copies just the HD bits, the boot sector, etc.
2010/6/24 C.J. Adams-Collier cjac@colliertech.org
I often use rsync -a for remote systems or cp -a for local systems. I've also used dd. You can have dd output to stdout, pipe it to ssh and have ssh output to dd on the other end.
You can also connect to a SAN device on the source and dd from the local block device to the SAN device.
Lots of ways to do it ;)
Cheers,
C.J.
On Thu, 2010-06-24 at 10:52 -0400, Kelvin Edmison wrote:
On 24/06/10 7:17 AM, "Poh Yong Hwang" yongsan@gmail.com wrote:
I have a server running CentOS 5.5 with KVM capabilities. I need to
migrate
all the VMs to another server with the exact same hardware specs. The
problem
is it is running on individual harddisks, not shared storage. What is
the best
way to migrate to minimise downtime?
I've had good success using dd and nc (netcat) to copy the contents of a disk or disk image from one machine to another, and verifying the copy
was
successful with a md5sum or sha1sum of both the original and copied disk.
Kelvin
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Note, the -x argument will keep the copy to a single partition
On Thu, 2010-06-24 at 14:12 -0300, Lucas Timm LH wrote:
Create a new virtual machine on your storage. After this, boot some Linux distribution in your new virtual machine (I like SysrescueCD). Enable your ssh server, change the root password and so and back to your old virtual server and type:
# dd if=/dev/sda | ssh root@(new_vm) "(dd of=/dev/sda)"
Type the root password, shutdown the old VM and reboot your new vm.
(PS: You don't need to shutdown the old vm to this proccess).
I do this everytime, I don't like copy the HD files using cp, tar or rsync because it try to copy the /proc, /dev and a lot virtual devices. Using dd it copies just the HD bits, the boot sector, etc.
2010/6/24 C.J. Adams-Collier cjac@colliertech.org I often use rsync -a for remote systems or cp -a for local systems. I've also used dd. You can have dd output to stdout, pipe it to ssh and have ssh output to dd on the other end.
You can also connect to a SAN device on the source and dd from the local block device to the SAN device. Lots of ways to do it ;) Cheers, C.J. On Thu, 2010-06-24 at 10:52 -0400, Kelvin Edmison wrote: > > > On 24/06/10 7:17 AM, "Poh Yong Hwang" <yongsan@gmail.com> wrote: > > > I have a server running CentOS 5.5 with KVM capabilities. I need to migrate > > all the VMs to another server with the exact same hardware specs. The problem > > is it is running on individual harddisks, not shared storage. What is the best > > way to migrate to minimise downtime? > > I've had good success using dd and nc (netcat) to copy the contents of a > disk or disk image from one machine to another, and verifying the copy was > successful with a md5sum or sha1sum of both the original and copied disk. > > Kelvin > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt@centos.org > http://lists.centos.org/mailman/listinfo/centos-virt _______________________________________________ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt-- Lucas Timm, Goiânia/GO. http://timmerman.wordpress.com
(62) 9157-0789
This can be useful in some cases: http://www.bouncybouncy.net/ramblings/posts/xen_live_migration_without_share...
With the blocksync.py script on that page you can first make a copy of the block device while the VM is still running. Then shut down the VM and make another run only this time you only have to copy over the bits that have changed during the previous sync. Depending on HD/CPU/Net performance this can reduce the downtime a bit.
Regards, Dennis
On 06/24/2010 11:22 PM, C.J. Adams-Collier wrote:
Note, the -x argument will keep the copy to a single partition
On Thu, 2010-06-24 at 14:12 -0300, Lucas Timm LH wrote:
Create a new virtual machine on your storage. After this, boot some Linux distribution in your new virtual machine (I like SysrescueCD). Enable your ssh server, change the root password and so and back to your old virtual server and type:
# dd if=/dev/sda | ssh root@(new_vm) "(dd of=/dev/sda)"
Type the root password, shutdown the old VM and reboot your new vm.
(PS: You don't need to shutdown the old vm to this proccess).
I do this everytime, I don't like copy the HD files using cp, tar or rsync because it try to copy the /proc, /dev and a lot virtual devices. Using dd it copies just the HD bits, the boot sector, etc.
2010/6/24 C.J. Adams-Colliercjac@colliertech.org I often use rsync -a for remote systems or cp -a for local systems. I've also used dd. You can have dd output to stdout, pipe it to ssh and have ssh output to dd on the other end.
You can also connect to a SAN device on the source and dd from the local block device to the SAN device. Lots of ways to do it ;) Cheers, C.J. On Thu, 2010-06-24 at 10:52 -0400, Kelvin Edmison wrote: > > > On 24/06/10 7:17 AM, "Poh Yong Hwang"<yongsan@gmail.com> wrote: > > > I have a server running CentOS 5.5 with KVM capabilities. I need to migrate > > all the VMs to another server with the exact same hardware specs. The problem > > is it is running on individual harddisks, not shared storage. What is the best > > way to migrate to minimise downtime? > > I've had good success using dd and nc (netcat) to copy the contents of a > disk or disk image from one machine to another, and verifying the copy was > successful with a md5sum or sha1sum of both the original and copied disk. > > Kelvin > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt@centos.org > http://lists.centos.org/mailman/listinfo/centos-virt _______________________________________________ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt-- Lucas Timm, Goiânia/GO. http://timmerman.wordpress.com
(62) 9157-0789
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
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C.J. Adams-Collier -
compdoc -
Dennis J. -
Kelvin Edmison -
Lucas Timm LH -
Poh Yong Hwang